1. Field of the Invention
The present invention relates to a film adhesion device and a film adhesion method, and more particularly to a film adhesion device and film adhesion method with which a structure having an extremely thin film thickness and a high film thickness can be formed with good yield and excellent thickness precision on a semiconductor wafer.
2. Description of the Related Art
In recent years, microdevices such as microsensors, microactuators, and optical switches formed by integrating minute elements that are created using semiconductor microprocessing techniques have become known as Micro Electro Mechanical Systems (MEMS).
In these microsensors and so on, a structure (for example, a hollow structure or the like) may be formed on a semiconductor wafer. Typically, the structure is formed by coating the semiconductor wafer with photoresist using a method as a roll coater method or spray method, and then performing exposure/removal processing and the like. Note that the thickness of wall portions 151 and a roof portion 152 constituting a structure 150 is extremely thin (30 μm or the like, for example) (see FIG. 17).
However, when photoresist is applied using a roll coater method in the conventional structure forming method described above, pin holes and so on are likely to form when the coating film thickness is reduced, and when the coating film thickness is increased, waves (indicated by the virtual lines in FIG. 17) and so on are likely to form. When the photoresist is applied using a spray method, the coating amount becomes unstable when a coating device is driven and stopped, and hence the yield is poor. Therefore, with the conventional structure forming method described above, it is difficult to form a structure having an extremely thin film thickness while securing a predetermined thickness precision (less than 5% or the like, for example). Defective structures occur particularly often at the two end portions of a semiconductor wafer having a small surface area.
Also, an extremely high degree of precision (for example, thickness precision, variation, impurity concentration, and so on) is required of the material constituting the structure, and it is technically difficult to manufacture a structure having a high film thickness. However, in applications for use in environments having high pressure, high temperature, high humidity, and so on, for example, products requiring structures with a high film thickness are needed.